Folk etymology and the origin of Cockroach

Folk etymology is a term used to describe the phenomenon of a word or phrase changing into something more familiar. This occurs most frequently when foreign or obscure words are changed in order to match what they define. Folk etymology is related to eggcorns, in the sense that an eggcorn could theoretically stick and become a new word that enters the standard lexicon.“Cockroach,” for example, comes from the Spanish “cucaracha”; it was folk-etymologized as a compound word combining “cock” and “roach.” Another example is the term “shamefaced” (meaning, simply put, ashamed), which comes from the obsolete “shamefast”, or “stuck in shame.” Other words formed by this process include:Kitty-corner, from the mostly obsolete “cater-corner.”

Bridegroom, from the Old English “bridgome.” Gome was then a word for “man.”
Crayfish, from the Old French “crevice.” The Modern French term is “écrevisse.”